Apparatus for constructing vibration-compacted concrete slabs



Feb. 8, 1949. A; E. MILLER ET AL 2,461,500

APPARATUS FOR CONSTRUCTING VIBRATION-COMPACTED CONCRETE SLABS Filed Oct. 4, 1944 5 Sheets-Sheet 1 zjwue/wtmw a0 27 a; firth Lll Eifilz'lle r,

3/ GeorgeK Ka'all and Feb. 8, 1949.

APPARATUS FOR 60M Filed Oct. 4, 1944 A E. MILLER ET AL STRUCTING VIBRATION-COMPACTED CONCRETE SLABS 5 Sheets-Sheet 2 awe/Whom! flrtharil jlljller,

Gewfge If, Via and Rudolph l 'fL/indow,

. Feb. 8, 1949.

CONCRETE SLABS Filed Oct. 4, 1944 V A. E. MILLER ET AL APPARATUS FOR CONSTRUCTING VIBRATION-COMPACTED 5 Sheets-Sheet 3 6&9. 5.

gvwem bo'w firth aha/Miller; 660736 E Vi'azll and fiudolphl fLz'ndau/g 7 Filed 001;. 4, 1944 Feb. 8, 1949. A. E. MILLER ET AL 2,451,500

APPARATUS FOR CONSTRUCTING VIBRATION-COMPACTED CONCRETE SLABS 5 Sheets-Sheet 4 avvuq/rvildb ,flrthurEJ fiZZer, George K Ve'aZL and RudolphJ'YLindow,

Patented Feb. 8, 1949 APPARATUS FOR CON STRUCTING VIBRA- TION-COMBACTED CONCRETE SLABS Arthur E. Miller and George K. Viall, Milwaukee,

and Rudolph F. Lindow, Wauwatosa, Wis., assignors to Chain Belt Company, Milwaukee, 7 Wis., a corporation of Wisconsin Application October 4, 1944, Serial No. 557,162

The invention relates to the construction of concrete slabs, and has for its principal object the provision of an improved apparatus for con structing reinforced vibration-compacted concrete road slabs having expansion joints between adjacent sections.

While susceptible of various embodiments with in the scope of the invention, for purposes of disclosure there has'been illustrated in the'accom panying drawings forming a part of this specification one form of apparatus constructed and arranged in accordance with the invention.

In the said drawings:

Figs. 1 and 1A together constitute a of such form of apparatus;

Fig. 2 is a side elevational view of the parts illustrated in Fig. 1;

Fig; 3 is a partial front'elevational view of the apparatus shown in Figs. 1 and 2, as seen from the left of the said figures; V

Fig. 4 is an enlarged sectional-elevational view of a portion of the drivemeehanism of the machine, taken approximately on the planes indicated'b'y the line 4-4 of Fig. 1, looking in the direction of the arrows;

Fig. 5 is an enlarged fragmentary cross-seetional view, taken on the plane indicated by the line 5-5 of Fig. 2;

Fig. 6 is a sectional-plan view, taken on the planes indicated by the line 6-6 of Fig. 4, looking down;

Fig. 7 is a fragmentary detail plan view of a portion of the mechanism for effecting and controlling longitudinal movements of one of the vibrator batteries; 7

Fig. 8 is a seotional-elevational view on approximately the planes indicated by the line 8-8 of Fig. 7, looking in the direction of the arrows;

Fig. 9 is a sectional-plan view, on the plane indicated by the line 9-9 of Fig. 8, looking downj Fig. 10 is a vertical sectional-elevational view, on the plane indicated by the line ill-Ill of Fig. 8, looking in the direction of the arrows;

Fig. 11 is a longitudinal sectional-elevational view of the apparatus shown in Fig. 1, taken on the plane indicated by the line ll-H of said figure, looking in the direction of the arrows;

- Fig. 12 is a view similar toFig. 11, taken on the plane indicated by the line l2-l2 of Fig. 1A;

Figs. 13 and 14 are enlarged fragmentary sectional-elevational views, taken upon the planes indicated by the respective lines l3--|3 and +14 of Fig. 12, looking in the direction of the arrows; f

Fig. 15 is a detail perspective View of one of plan View 10 Claims. (Cl. 94'48) the elements employed at the expansion joints in the pavement to facilitate passage of the vibrat-v The present apparatus is designed to be sup- 7 ported by and to travel upon the forms or rails F which are customarily laid upon a prepared sub-grade to define the lateral edges of the concrete road slab, and in order that the apparatus may be readily accompanied to the construction of slabs of different; widths, it is preferably composed of a plurality of separably connected units such as A, B and C (Fig. 1). For a road of less width than that indicated in said figure, a unit similar to but of less width than the intermediate unit B may be substituted for such unit, or the saidunit may be removed completely and the units A and C directly connected together, while for roads of greater width than that indicated.

a B unit of greater width may be substituted for the one shownyor a second B unit may be introduced into the machine, all as will be readily understood.

The unit A comprises a rectangular frame which includes end members Zlla and 21a and.

longitudinal members 22a, 23a, 24a and 25a rigidly connected thereto. At their forward end the longitudinals 24a. and 25a respectively carry suitable bearings 26a. and 21a, in which is journalled a transversely extending shaft 28a which rigidly carries a flanged supporting wheel 29a and a' gear 30. As best shown in Fig. 6, the said gear meshes with a companion gear 3l which is loosely mounted upon a countershaft 32 journalled in bearings 33 and 34 carried by the longitudinals 24a and 2511. respectively. The saidgear 3| is provided with clutch jaws 35' which are adapted to be engaged by companion clutch jaws 36 formed on one end of a shiftable clutch member 31 which is splined on the counter-shaft 32. The other end of said clutch member 31 is provided with clutch jaws 38 which are 'engageable with companion clutch jaws 39 carried by a sprocket 40 which is loosely mounted on the countershaft 32. A drive chain 4| is trained about the sprocket 40 andabout a companion sprocket 42 which is rigidly carried by ajack shaft 43 journalled in bearings 44 and 45 carried by the longitudinal members 24a and 25a. The said jack shaft also rigidly carries a sprocket 56 which is driven by a chain 41 from a sprocket 48 carried by the output shaft 49 of a reducing gear mechanism 59, which is driven from any suita le source of power .1 ch,,for example, as. an internal combustion engine 51 mounted upon the longitudinal frame members 24a, and 25a, see Figs. 1 and 2. I

The countershaft 32 also rigidly carries a gear 55 which meshes with a companion gear 55, loosely mounted on the jack. shaft 43 and provided with a jaw clutch 51 adapted to be engaged by a companion clutch element 58 formed on a shiftable clutch member which is splined on the jack shaft 43.

The countershaft 32 has asprocket 5B keyed to it which, through a chain Bl, drives a sprocket 32 rigidly carried by a transverse shaft (i312, journalled in bearing brackets 64a. and 85a carried by the transverse frame member 23a. The bracket 65a also journals the shaft 286;, as will be clear from Figs. 3 and 10..

At the rear end of the framework, adjacent the transverse member 21c, the longitudinals 24a and ctcarl'y bearings BBaVand 61a, which journal a shaft 58a carrying afianged roller 69a. This roller and its companion forward. roller 29a. constitute a pair of supporting wheels fo the frame. which are adapted to rest p n and traverse one of the forms or rails F, as will be readily understood from Figs. 1, 2 and 5. A shaft 1.8a .is also mounted at this, end of the framework, being journalled in bearing brackets Ha carriedv by the frame member Zia. This shaft carries a pair of transversely spaced sprockets 12a, andJSa, about which chains 14a,

and 150; are trained. These chains extend forwardly to and about sprockets 15a and 11a carried by a sleeve [81; which is loosely mounted on the shaft 631;. .As best shownin Figs. 7-10, the sprocket 'lfiais provided with clutch jaws 86a.- which areengageablee by companion clutch jaws 810. formed on a shiftable: clutch member 82:; which is-splincd oaths-shaft 630.. i The member 82a is shiftableon. the; said shaft: to engage and disengage the clutch elements 88c and Me. by meanscfa pair of arms-8 3a carried by a sleeve 84a which is keyed to a spin-- dle 850, which is journalled in a vertical hearing sleeve 86a which is part of the, bearin bracket structure a. Atv its top, the spindle 85a rigidly carries an operating. arm 81w by means of which the spindle may, be moved to shift the clutch elementtlo into engagement with the companion'element 813a,, whereby the sprockets 'lfia, and'l'la and their chains "a and 15 may be driven from. the shaft 63a.

The longitudinal members 22a and 23a of the frame constitute supporting guides or trackwaysfor a carriage 5011 which ,is mounted thereon by rollers 9m, (Figs. 8 and 9). The said carriage is attached to. the upperv run of the chains 14a and 150. as bybrackets 89a, and thus is traversable along the members 22a. and 23a longitudinally of the frame, whenthe said chains are driven from the shaft 63a, as aboveexplained. Toprevent over-travel of the carriage in the forward, direction the upper runof the chain Ma. is. provided with aknock-out dog 92a, which, when the carriages reaches substantially the position illustrated in Figs. 1, 7 and ;8, engages and moves, an arm 93a carried by thesleeve 84av whereby the latter, through its shifting, arms 83a, cliseiistfltsv the clutch elements 88a, Bla to break the drive to the chains 14a, 15a. In like manner, the lower run of the chain Ma carries a knock-out dog 94a which is engageable with an arm 95a of the sleeve 84a. to cause disengagement of the clutch when the carriageflreaches its rearward limit of travel.

Mounted, upon the carriage a is a battery of motive units 960., such for example as electric motors, each of which is connected by an armored flexible shafting 91a to a vibrating mechanism 98a, of any suitable construction. The shafts 8111 are of such length that the vibratorsSSu. may trail behind the machine by :say 10 to .20 feet.

Except thatit has no prime mover and drive gearing. the construction of the the unit C of the machine is much the same as that of the A unit just described; and the elements of the former. unit which correspond to those of the latter are designated by like reference numerals with c exponents. The C unit also differs from the A unit in that its rollers .29cand 69c, instead The intermediate 3 unit is alsoslargely similar to the A unit, except that it has no drive mechanism and supporting rolls; and its corresponding parts are designated by like reference numerals with b exponents. As will be readily understood from Figs. 1 and 3, the B unit is disposed between the A and C units, to which it is rigidly but sepa rably attached by connectionssuch as the bolts88. The alined shafts 28a, 28b and 28s are connected at their joints by suitable shaft couplings 99, while the shafts 63a, 63b and 630 are connected by similar couplings I00, one oiwhich is shown in Figs. 9 and 10. I

It is contemplated that the machine will be moved only intermittently on the forms F, andto hold it stationary between movements'the units A and C are provided with eccentric brake shoes Mia and NH 0 carried by shafts "32a and Ill-2c and engageable with the respective for-ms F in front of and behind the machine, as shown in. Fig- 2. The shafts "32a, I02?) and (Me are connected by shaft couplings I03 so that all four brake shoesmay be simultaneously operated by a lever IM- through rods I05 connected. to the shoes Hlla.

As is well known, under present'practice the concrete mixture for a large percentage of the concrete roads constructed today is furnished by a specializedtype of concretemixer known as a paver which is advanced intermittentlyon the.

subgrade between the forms. F, and is provided with a distributing bucket travelling upon a rearwardly extendin horizontally; oscillatable boom, by means of which the mixture is conveyed from the mixing drum anddeposited on the sub-grade;

The present machine is low enough that when mounted upon the forms F; as shown in Figs. 2,1 3 and 11, it may be positionedv directly behind the paver, beneath the boom thereof; without inter-- fering with the travel of the distributing bucket on such boom. Thus the'mixture from the paver drum may be'conveyed by the bucket tothe rear of the vibrating machine and deposited on the road bed to fill the space between the forms F and cover the vibrators 88a, 98b and 980, and upon the latter being actuated by their motive units 96a, 96b and 960 the plastic mixture will be subjected to internal vibration which compacts and densiflesit in a manner well understood by those skilled inthe art.

At the beginnin of a cycle of operation, with the vibrating machine in place upon the forms F behind the paver, its several clutches disengaged, and longitudinal movement on the forms restrained by setting of the brakes Hila, He, the several carriages 90a, 90b and 90c are all moved to their rearmost position, i.e. the position in which the carirage 900 is illustrated in Fig. 1, and the several vibrators 98a, etc. are disposed upon the road bed as far to the rear of the machine as is permitted by the length of the flexible shafts 9111, etc. Concrete from the paver is then deposited by its distributing bucket in the area occupied by the vibrators and the latter are operated by their motive units 96a, etc. to compact and densify the mixture by their internally applied vibrations. As the deposit of concrete progresses the vibrators are slowly drawn forwardly through the mixture in the followin manner:

Referring more particularly to Figs. 4 and 6, if the output shaft 43 of the gear mechanism 59 be rotating in a counterclockwise direction, as viewed in Fig. 4, the chain 41 will drive the jack shaft 43 in like direction and the sprocket 40 (loose on countershaft 32) in turn will be simi-.

larly driven by the chain 4 I. If new the shiftable clutch member 31 be moved to engage the clutch elements 38 and 39, the countershaft 32 will also be driven counterclockwise, which motion will be transmitted through sprocket 53, chain 6! and sprocket 62 to the transverse shafts 63a, 63b and 630. Upon shifting of one or more of the levers such as 81a the clutch elements such as 83a, 8la, controlled thereby will be engaged and the motion of the shafts such as 63a will be transmitted to theirassociated sprockets such as 150., 11a thereby causing the chains such as Ma, 15a to move the carriages 90a etc. from right to left, as viewed in Figs. 1 and 11, and thus draw the vibrators 93a etc. forwardly.

This forward motion of the carriages and vibrators may be interrupted at any desired point by manual disengagement of the clutches a, 8la etc. by means of their control levers such as 81a, but if permitted to continue until the carriage reaches the position of carriage 90a in Fig. 1, the motion will be automatically discontinued at this point by reason of the engagement of the dog such as 9211 with the arm such as 93a which will cause the shifting fork 83a to move the clutch member 82a to disengaged position, thus breaking the drive from shaft 63a. I

The carriage motion may also be reversed, by reversing the direction of rotation of the shafts 63a etc., which may be accomplished by moving the clutch member 31 to neutral, as shown in Fig.

6, and then moving the clutch member 59 to engage the jaws 57 and 58. The direction of rotation of the countershaft 32 andconsequently'of the shaft 63a will now be clockwise, since the drive from the jack shaft 43 to the countershaft 32 is now through the intermeshing gears 55 and 56. Ordinarily this reversed drive of the carriages will be employed only while bodily advancing the machine to a new position on the forms F, its purpose being to maintain the vibrators 98a etc. relatively stationary on the sub-grade during such advance. The reverse motion of the carriages will also be automatically discontinued when they reach the position relative to the frame in which the carriage 930 is illustrated, since at this time the dog such as 94a carried by the lower run of the chain lla will engage the arm 95aof the clutch shifting mechanism and disengage the clutch elements such as 80a, 8la.

- When the paver is moved forwardly to a new position on the sub-grade the present machine.

may be advanced along the forms to keep pace therewith if, with the clutch elements 51 and 58 in engagement, the clutch member 31 is shifted to engage the jaws 35 and 36, which will result in counterclockwise rotation of the shafts 2811, etc.

and the supporting wheels 29a and ZSccarriedthereby, from the now clockwise rotating counter-.

shaft 32 through the gears 30 and 3 I. To prevent the possibility of inadvertent simultaneous oppositely directioned drives to the countershaft 32, through the chain and sprocket drive 40, 4|, 42

on the one hand and the gears 55 and 56 on the other, the clutch members 31' and 59 may be pro'-.

vided with any appropriate form of. interlock to make it impossible to engage the clutch jaws 38 and 39 when the clutch elements 5! and 58'are engaged. i

As is well known, it

paratus is of value in this connection, as will be understood from Figs. 1A, 12 and 13, wherein suitable lengths of such fabric H0 are shown as deposited between the forms F, resting upon the flexible shafts 91a etc. and the vibrators 98! etc. When the latter are operated their vibrations ofcourse will be transmitted to the fabric strands;

and as the vibrators are drawn along the sub-' grade they will elevate the fabric above the subgrade so that it will become incorporated in the slab at an appropriate distance between the upper and lower surfaces of the slab.

It is also common practice to provide expansion joints in the roadway, usually by incorporating strips of compressible material in'the concrete at suitable intervals. These strips ordi narily extend from top to bottom of the slab and since they must be set in place transversely of the road bed in advance of the vibrators, provision must be made for drawing the latter and" their flexible shafts through the joint strips. One such strip is illustrated in Figs. 1A, 12 and 14f at I I2, and as will be clear therefrom the lower portion of the strip is provided with a plurality of spaced openings or notches H3 through which the flexible shafts 91a etc. may initially extend,

and through which the vibrators themselves may be drawn when advanced as above described, as shown in Fig. 12. To prevent the concrete mixture from working into such openings, whereby it might interfere with the passage of the-vibrators through the openings and might also form a continuous concrete bridge of the joint with the next slab section, the openings are each preferably temporarily protected by shielding devices Ill.

bridge member I I6 welded to them and which may also serve as a handle for manipulating the device. As will be readily understood, one of theseshielding devices is straddled over the joint Strip at each opening I I3 therein and as best indicated in Fig. 12 prevents the concrete from reaching such' opening. After'the vibrators have been drawn through-the openings,'the shields H4 are lifted is the present daypractice to reinforce most concrete road slabs with steel" 7-. out "snag-small pieces 4:12! :of ethe 'iointfimaterial (Fig. 1A) are placed in aposition T120 mover'zthe openings H3, after which ithe small voids :leit by the shields may :be :filled with concrete rby :hand. iTo maintain ithe vibrator fshazitszaml xvi-bras tors in *proper transversely spaced nelation, loneor. :more ,guide structures lanay .be employed :between :the machine .and :the vibrators. {Qne mi these devices is shown in Figs. .I'A, 212mm 31853-5 comprising an angle ironimember can rpm ided at its ;ends with rests '12 J iiorfsupponting mpon the riorrns if, and with handles M2 :bystihich :it may betsmanipulated. ilhis anemberniig'idlygcars ries a plurality -.of :pairs :or mdsmor singers iii-3 which extend downwardlyaoatheisubgenade.' The fingers. are so spaced :bhdt't-WhEHSUhBTmBYX'I-XIBT7'26 placed-in position on the itosnanathesubr gradeathe pairsnfifingersawillgaot asrguidesaiormhe several ifiexible shafts :195la etc. to zpreiaent .rlateral displacement of the :latter r-as they rare drawn along the sub-grade. This guide device OfLBQlHB iszremoved irom theriormszas the deposit ;of concrete reaches its vicinity; :and it :pte'ferehly constructed as zaxpluralityaci zunits separably con.- nected, as-at 2124 and corresnonding 'zto "113116 nn-its A, B and C f the machine so that'iitr mayrJoeza-iocommodated to :roads :ofyarious widths.

In order that the distance :above :the q-subsgnade at'WhiCh -thB rein'forcingzmesh cm danositioned win the slab :may:bezvar.ied tmsuitadiiferentvconditiqn or specifications, the vibrating devicesdfla, 15th. 980 may :be TDI'OVidQd avith adjustable supporting means -ior the mesh, as-shogvninfiss. -16 and Thatis :to say, the housingscf the: said vibrating devices may have rigidly-secured tothemalongitudinally extending angle bracket li il, tothe up. Standing-leg of which a mesh-supportingistri ior plate BI is {adfinstably ecured :by ihnlts asse sriedbyatherbracketrand pas ing through elongatedslots 433 in thesaid plate. :1 0 i sure that these mesh-supporting elements are always upper most, the vibrator housingameyalso beprovided at eachside with a longitudinallyextending-shoe L34-engageable1with thesuh gnade ;to;nrevent the vibrators from rotating about gtheir @(XQS, tvil 1 be readily understood.

These adjustable mesh-supporting-galernents.aige of. advantag notonly in enahlingzthe distancebetween :the sub grade and mesh gtofbe increased or decreased uniformly across the slab, but also in securing uniformity of .depth :of the mesh below thenpper surface ofatheslabrqsardlessiof vania.-

ticnsin the thickness of :the latter. Eosexampie,

in many .oases :slabs are constructed which. -.are thickeradjacent theiosms Ftthan;in-,theieenterrusually accomplished by contouring of the :snhgrade-r ared if in such instances the @KlQShPSllP porting members .131 .of the side vibrators 33a and QSc-be adjusted tooccupy higher positions thanthemembers -l.-3-lof thecenter vibrators uniform depth of the mesh below the slab seriace maygbesattained.

Whatis. claiinedis 11.; In sapparatus f or. constrncting vib rati ne co n pacted concrete slabs: a frame provided with power driven 'Ineans for advancing ;i t dnfiermi-ttently over.-a.slab bed; vibrating amean'siinclnding eleinentsdisposa'ble .upon the shed. in -:s1.'5ace i $312k r1011 wsaid f ame an iwn sclla l r on est ns between said 7 power driven means andxthe wibrating means whereby said elements nes :be noved over the bed toward the irame.

In .W J' JW che atics mentionqQmph -fi .wn si 13Q5 {a mob e. sa e: *QEWB nsan .i r m it sai .i em nea a slab as:

8 vibrator means -.comprising :a motive has, :a bration element disposable upon the shed inaspacd relation to :theiframe, :andio'perating connections between .said :element and unit; means vam'ovablv mounting :said motive .unit upon the frame; and meanssoperable by said drive means .to :move the motive :dnitzupon :the frame and thereby draw the vibration .element lover :the \bed :towardtthe frame.

.8. :In' apparatus for constructing zvibratiom compacted Tconcreteslabs: .a :mobile frame; drive means :for moving said .frame .over .a 5518'?) 'abed; a .carriage mounted "for movement .upon zthe frame; vibrator :means including a motive innit mounted on said .catr-iage, a ivibration element disposable :upon the :bed inspaced relation .to the frame, and operating connections between said element and :nnit; :and controllable connections betweensaiidtdriveimeans and thecarriageiwhereby .the latter may 'beamoved .upon the frame :to draw :thevibration element :over zthe died toward the frame.

in apparatus for constructing vibrationcompactedlconcrete:slabs: :a mobile irame; drive means for moving said frame .over ,a slab bed; a vibration element disposable upon the 'bed horizontally spaced relation totheiframe; means connectible ito said drive 'ineanszfor moving said element rover the bed .toward ethe frame; and means for automatically disconnecting said .element mcving -meansirom the drive meansasthe element approaches the frame.

15.121 apparatus for constructing Vibrationcompacted concrete slabs: :a :mobile frame; drive means for moving said irame over. .a :slab bed; .a vibrator :device including an element disposable upon ithe ;bed in horizontally .spaced :relation :to the frame; .reciprocatable means :upon the frame connected-to said device andoperableiby. sa d d ive means ito move .said vibrator element over the bed .=toward :the irame; and means operableat {the limits .of .travel of "the :reciprocatable means :to disconnect it from the drive means.

(6. fin apparatus .ior {constructing tvibrationcompacted concrete slabs: a :mobile frame; drive means ff-or :moving said :irame over :a slab shed; a vibrator device vreciprocatably mounted on {the frame and having a vibration element disposable :upon the bed in horizontally :spaced melation to :the drama; a shaft driven by said drive means; iconneotions between said shaft and the vibratordevice for moving the latter upon the frame @to draw the vibration element over the bed toward :the :frame; and clutch means for controlling said connections.

iIn apparatus for constructing vibrationcompacted: concrete :slabs: a .mobile frame drive means for moving'said frame over @a slab ibed; a vibnator :device reoiprocatably qmonnted 1 on :the frame and having-a vibration element disposable on itbe bed in horizontally spaced relation to the frame; chain and sprocket'machanism connectedto said-yibrator device for moving :the 1 latter upon the :frame to :draw the vibrationelement over :the bed .t-owardrthe I-irame; and :reversible connections hetweenisaid chain and sproc,ket mechanism and said drive means.

i8. in apparatus for constructing vibrationcompacted concrete slabs: 1a mobile :frame comprising ga plurality of ,separahly connected units; a shaft .oommon to all of said .units, comprising separably connectedsections carriedbmthaunits; means tor :driving :said .shaft; 2. vihrator device reciprocatably-mounted upon each of said frame Elm hi m cs V 'P Es'i iQE e m nt d s osable ssni sle hesl an means e -s co dha d meeting and disconnecting said vibrator devices to and from said shaft whereby said devices may be independently moved upon the frame to cause travel of their vibration elements over the bed.

9. In apparatus for constructing vibrationcompacted concrete slabs between spaced pre-set forms: a mobile frame provided with means whereby it may be intermittently moved over the slab bed; vibrating means disposable upon the bed in horizontally spaced relation to said frame; brake means engageabie with the forms to iii-- termittently restrain movement of the frame over the bed; means movably carried by the frame and connected to said vibrating means, for traversing the latter over the bed; and means for moving said traversing mean-s upon the frame when the latter is stationary, to cause the vibrating means to approach the frame.

10. In a device for applying vibrations to a plastic concrete mixture, a substantially cylindrical Vibrator housing adapted to rest upon a bed for the mixture; a member etxending upwardly from said housing for engaging and supporting a concrete reinforcing element; means connecting the member to the housing for vertical adjustment relative thereto, whereby the reinforcing element may be supported at various distances above the housing; and bed-engaging shoes car- 10 ried by the housing forpreventing turning of the housing on its axis.

ARTHUR E. MILLER. GEORGE K. VIALL. RUDOLPH F. LINDOVV.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date Re, 17,361 McInerney July 2, 1929 ,271,010 Billington July 2, 1913 1,533,035 Arnett Apr. 14, 1925 1,562,257 Rogers Nov. 17, 1925 1,571,527 Rhodes Feb. 2, 1926 1,768,350 Edge 27, 1930 1,784,385 Pelton Dec. 9, 1930 1,969,884 Heltzel Aug. 1&1, 1934 2,021,981 Mitchell Feb. 25, 1936 2,956,198 Hahn Sept. 29, 1936 2,077,356 Day Apr. 13, 1957 2,138,103 Jorgensen Nov. 29, 1933 2,245,163 Mallson July 8, 1941 2,259,110 Jackson Oct. lei, 1941 2393335 Day Dec. 1, 1942 

